Paint everything white. Walls and ceiling interior shelves etc. Huge difference in lighting efficiency over light brown for example. You are correct on the floor. Those little flakes look cool but are a bitch to live with. Can't find anything smaller that a 1/2" size bolt on it. I worked in a Electronic shop that was going to use them and I nexed that idea because of that very problem. Small parts on the floor stayed there until it got swept and then everything got thrown away. Big waste of money.
I had that shop floor and office (7500+ sq /ft) done in the very light color grey with no flakes. Worked very well for years. I should have had my home shop garage done the same way but I didn't too try and control costs, It got a bit crazy and I had to cut something. I wish I hadn't now...……………….. Nice looking building.
Wire for 220 single phase a couple of places along the walls. Welder, mill, lathe, air compressor etc.
I used roll up doors. That's where the budget got blown, but I'm really happy I did. No overhead interference from the garage doors when opened. Really great. I love them.
I recommend all LED lighting. A bit more money but I haven't changed a bulb yet. Going on 3 years.